Boiler

ABSTRACT

A boiler comprising a housing adapted to contain water. A combustion chamber located in the upper portion of the housing and a heat exchanger located in the lower portion of the housing. The heat exchanger holds a quantity of water for consumption. A duct is located within the housing connecting the space above the combustion chamber and the space below the heat exchanger. A pump is provided to circulate the water in the housing through the duct.

United States Patent Hans Viessmmn 3559 Batteuberg im Haln, Germany 868,158

Oct. 21, 1969 Aug. 24, 1971 Oct. 24, 1968 German Inventor Appl. No. Filed Patented Priority BOILER 8 Claims, 3 Drawing Figs. I

US. Cl. 122/37 Int. Cl. F22b 33/02 FieldofSearch l22/32,33, 37,494

[56] References Cited UNITED STATES PATENTS 3,007,457 11/1961 Ospelt 122/37 3 366,094 1/1968 Viessmann 122/494 Primary Examiner- Kenneth W. Sprague Attomey- Kurt Kelman ABSTRACT: A boiler comprising a housing adapted to contain water. A combustion chamber located in the upper portion of the housing and a heat exchanger located in the lower portion of the housing. The heat exchanger holds a quantity of water for consumption. A duct is located within the housing connecting the space above the combustion chamber and the space below the heat exchanger. A pump is provided to circulate the water in the housing through the duct.

Patented Aug. 24, 1971 '5 Sheets-Sheet 1 Fig.1.

MERIT Patented Au 24, 1971' 3,601,097

3 Sheets-Sheet 2 Fig-2 Inventor:

Patented Aug. 24, 1971 3 Sheets-Sheet 5 Wm WM mm m mg 1 W W m v V DD BOILER The invention relates to a boiler which is suitable both for heating and storing water for consumption and which comprises a water-carrying housing with forward and return flow connections, in which, in addition to a combustion chamber, there is a heat exchanger such as a hot water tank, a continuous flow heater or the like for developing and, if desired, storing water for consumption.

Such boilers are known. The heat exchanger for heating water for consumption is generally arranged beside or above the combustion chamber.

The heat exchanger is either incorporated into the water chamber of the boiler or is mounted on the boiler as a separate unit and is linked with the boiler by means of hot water pipes, particularly if the heat exchanger is a hot water tankand not a continuous flow heater. For purposes of simplicity in the following reference is only made to hot water storage tanks, although fundamentally the same arrangement can be used also for continuous flow heaters or for hot water storage tanks and continuous flow heaters together.

To accelerate the heating of the hot water heater it is usual to fit in the hot water pipes a circulating pump also called a charging pump. This charging pump makes it possible to regulate the temperature of the water for consumption to be heated, i.e. the hot water. To this end a thermostat is incorporated into the hot water heater which switches on the pump on dropping below the desired value and disconnects said pump on reaching the desired value.

Regulation of the hot water temperature, i.e. an upward limitation of the hot water temperature, can be important for various reasons, for example if the water is corrosive. If galvanized steel pipes are used as hot water pipesthe corrosive action of the water can be reduced by limiting the hot water temperature to, for example, 65 C. If the water is very hard, by limiting the water temperature the deposition of the hardening constituents in the water heater and the hot water pipes connected at the outlet side can be reduced.

Due to present-day water conditions the corrosion problem is becoming increasingly serious. Galvanized steel pipes can still be used only in certain areas. In fact in many areas the water corrodes iron materials. Hot water pipes should really be of copper, but copper prices vary considerably. As a rule copper is extremely expensive, so that generally the high cost of copper pipes represents a great handicap.

Plastic pipes are indeed corrosion resistant with respect to drinking water but are sensitive to temperatures above 60 C. For plastic hot water pipes it is absolutely necessary to have an upper limit on the boiler temperature.

Boilers with separately mounted storage tank and charging pump are very expensive to manufacture.

The present invention is intended to solve the problem of providing a boiler of the type mentioned suitable also for heating and storing water for consumption, which with a simple construction and a minimum number of pipes in or on the boiler offers good possibilities for regulating the water for consumption to be heated.

According to the invention there is provided a boiler comprising a housing intended to carry water and having forward and return flow connections wherein there is in addition to a combustion chamber a heat exchanger such as a hot water tank, continuous flow heater or the like for developing and, if desired, storing water for consumption, the interior of which housing has at least one heat exchanger arranged beneath the combustion chamber, the housing space above the combustion chamber being connected with the housing space below the heat exchanger by a duct which in use permits water to circulate and which is provided with a pump.

As a result of this solution the pipes necessary in or on the boiler are reduced to a minimum and both the combustion chamber and the heater or storage tank for the water consumption are disposed in an inner chamber conveying the heating medium and in a housing having no partitions.

The heat developed in the combustion chamber which is passed on to the heating medium rises. The heating water at the bottomdoes not become heated, i.e. the heating water below the boiler zone, where heat is developed by oil or gas burners, is only heated at the level of the heat source. By the incorporation of the combustion chamber and, hot water heater in one housing manufacturing costs can be reduced.

The circulating pump serves for heating the tank for consumption water which via a pipe or duct in the boiler heating water draws off the hot water from above and forces it downwards into the hot water heater area. When the hot water heater has reached the desired temperature a thermostat on or in the hot water heater switches off the pump.

In this design only one pipe is necessary whereas for a superposed hot water heater two are necessary. The pipe arrangement is therefore much simpler and costs considerably less. Therefore no pipes need be fitted to the outside of the boiler, although this would of course be possible.

Such an arrangement would not only be possible for boilers with oil or gas burners but also for boilers heated with atmospheric gas burners. With such gas burner boilers it would be necessary to arrange heating gas flues above the gas flame which should provide a vertical heating gas distribution.

The arrangement would also be possible for boilers electrically heated by resistor elements and cartridge heaters. However, a combination is also possible, where instead of a boiler or electrical resistor elements pipe coils are used, through which flow a heating medium at high temperature and under high pressure, as is the case, for example, with long-distance heating. Long-distance hot water is preferably not used directly from the boiler connection. Space heating is heated indirectly in that a heat exchanger is used. In the present version a heat exchanger for the water heating and a heat exchanger for the space heating is used. There are also combinations where the hot water heater and heating coils for the long-distance heating water are incorporated into one housing, but then the pipe coils are arranged under the hot water heater and the hot water temperature can either not be regulated or only with difficulty.

lf therefore subsequently and in the claims reference is made to combustion chambers this does not mean that the arrangement according to the invention can only be used therewith, because it can, in fact, be applied generally to all types of heat source, i.e. also gas burners, heat exchangers, or the like mounted in the water-carrying inner chamber of the boiler.

The following comments are made regarding the corresponding arrangement of continuous flow heaters:

There is at present a certain prejudice in expert circles against continuous flow heaters, although hot water heating by continuous flow heaters necessitates lower constructional costs than hot water heating by storage tanks. At too high water temperatures scale is deposited in the pipes of the continuous flow heater. If, according to the invention, it is possible reliably to regulate the water temperature, i.e. if the water temperatureis not allowed to rise above 60 C., a deposition of the minerals dissolved in the water only takes place to a limited extent. In order to reduce or prevent corrosion in hot water mains connected on the outlet side it is desirable that the water temperature is not allowed to exceed 60-65 C. which for example, with galvanized hot water pipes is very important because at 65 C. a reversal of potential takes place. The galvanized coating is then no longer able to protect the iron material from which the pipe is made and corrosion occurs.

The regulation of the hot water temperature, i.e. the upward limitation of the hot water temperature to 60 C. or 65 C. is important for three reasons: (1) to avoid or reduce the deposition of materials dissolved in the water; (2) to avoid or reduce corrosion in hot water pipes connected on the outlet side when these are made of iron materials; and (3) to prevent scalding when supplying hot water, for example in the bath or when washing hands.

For points (2) and (3) it is not absolutely necessary to limit the hot water temperature in the hot water heater because with mixer batteries behind the hot water heater the hot water temperature can be regulated and upwardly limited by admixing cold water from the supply main.

It has been found that large circulating pumps are not necessary. A pump for a boiler up to 100,000 calories output costs relatively little. The pipe for drawing off hot boiler water from the top of the boiler and directing it down to the storage tank or continuous heater can be cheaply and simply produced. The downward leading pipe at the same: time contains the casing for the pump and can be in the form of a single stamping. The casing can be welded at the bottom to the boiler rear wall, so that a complete pump does not even have to be provided, but only a motor with impeller, which is then simply screwed onto the casing.

The solution according to the invention is not only advantageous due to the possibilities for regulation but because, as shown, by downwardly directing the hot water flow the heat absorption can be increased by the increased flow rate of the heating water, whereby the relatively small AT in comparison with an arrangement above the combustion chamber can be compensated again, i.e. with the hot water heater arranged below the boiler there is approximately the same hot water capacity despite the low AT, because the pump and the special guiding of the heating water flow lead to a relatively high flow rate of the heater water and the heat transfer on the heating surfaces of the hot water heater is increased.

Further details will now be described in greater detail with reference to the accompanying drawings of two embodiments of the invention:

H6. 1 shows a longitudinal section through the boiler of one embodiment,

FIG. 2 is a cross section through the boiler, and

FIG. 3 is a view similar to that of H6. 1 of another embodiment.

In the upper part 2 of a boiler housing 1 are arranged the combustion chamber 3 with heating gas flues 4 and burners 5, while in the lower part 6 of the boiler is installed the consumption water heater or storage tank 7, which can be naturally have a shape other than that shown.

Thus the combustion chamber 3 and the consumption water heater 7 are located in the same water-carrying inner chamber of housing 1 and are not separated from one another by any partition.

A pipe 9 is provided in the water-carrying inner chamber 8 in order to bring hot heating water from the top to the bottom for heating the water for consumption tank 7 which pipe with the interposition of a pump 10, extends from the boiler upper part 2 into the boiler lower part 6 and preferably from an area above the combustion chamber 3 to an area at least in the lower half ofthe tank 7.

h pper portion 9 of pipe 9 is connected to the pump 10 on the suction side and the lower portion 9" on the pressure side, in the embodiment shown said pump is located outside the boiler housing 1 which at this point has a corresponding connection aperture. Obviously the pump 10 with its suction aperture could be connected directly with the water-carrying inner chamber in the upper part 2 dispensing with a pipe portion 9' and conversely by its pressure side dispensing with a pipe portion 9" with the inner chamber in the lower part 6.

The version with the continuous flow heater arranged below the boiler offers considerable economic advantages with larger boilers, because with the continuous flow heater the heat developed by the boiler can be converted in an inertialess manner into hot water. Very high capacity continuous flow heaters have considerably smaller external dimensions than storage tanks. It is in practice impossible with boilers having, for example, a capacity of 1 million calories to incorporate hot water storage tanks into the boilers which are large enough to even nearly utilize the boiler capacity for hot-wat er-heati pur oses.

e solution described can naturally also be used in boilers wherein the storage tanks or continuous flow heaters are placed in separate housings, whereby however the water-carrying inner chambers of the boiler and storage tank or continuous flow heater would have to be connected in such a way that the hot water supply pipes would pass from the upper part of the boiler into the lower part of the water for consumption heater(s), while the discharge pipes would pass from the upper part of the water for consumption heater(s) into the lower part of boiler water jacket. A charging pump is then in serted between the boiler and the water for consumption heater.

To avoid redundancy in the description, like reference numerals designate like parts in the embodiment of HO. 3. As shown therein, a plurality of heat exchangers 11 are located within the housing in water consumption tank 7 below the combustion chamber. A thermostat 12 is mounted in tank '7 and is connected to pump 10 to control the same.

What I claim is: I

l. A boiler comprising a housing adapted to contain water and having forward and return flow connections, a combustion chamber spatially located in the upper portion of said housing, a heat exchanger spatially located in the lower portion of said housing, said heat exchanger adapted to contain a quantity of water for consumption, a duct connecting the space above the combustion chamber with the space below the heat exchanger, and a pump connected to said duct for circulating the water within said housing whereby hot water from the upper portion is moved into contact with the heat exchanger in the lower portion.

2. A boiler according to claim 1 wherein the circulating duct is in the form of a pipe in the interior of the housing the upper opening of the pipe being above the combustion chamber and the lower opening being below the heat exchanger, the circulating pipe passing through the pump which has its suction side connected to the upper part of the pipe.

3. A boiler according to claim 2 wherein the pump is arranged outside the interior of the housing.

4. A boiler according to claim 2 wherein the pump is arranged approximately in the region between the combustion chamber and the heat exchanger.

5. A boiler according to claim 4, wherein the pump is thermostatically controlled, the control thermostat being connected to the heat exchanger.

6. A boiler according to claim 2, wherein the circulating pipe serves as a pump housing over a clearly defined area.

7. A boiler according to claim 1 wherein a continuous flow heater is provided and having a mixing regulator between the pump and the suction aperture of the circulating pipe.

8. The boiler according to claim 1, including a plurality of heat exchangers located within said housing, all below said combustion chamber. 

1. A boiler comprising a housing adapted to contain water and having forward and return flow connections, a combustion chamber spatially located in the upper portion of said housing, a heat exchanger spatially located in the lower portion of said housing, said heat exchanger adapted to contain a quantity of water for consumption, a duct connecting the space above the combustion chamber with the space below the heat exchanger, and a pump connected to said duct for circulating the water within said housing whereby hot water from the upper portion is moved into contact with the heat exchanger in the lower portion.
 2. A boiler according to claim 1 wherein the circulating duct is in the form of a pipe in the interior of the housing the upper opening of the pipe being above the combustion chamber and the lower opening being below the heat exchanger, the circulating pipe passing through the pump which has its suction side connected to the upper part of the pipe.
 3. A boiler according to claim 2 wherein the pump is arranged outside the interior of the housing.
 4. A boiler according to claim 2 wherein the pump is arranged approximately in the region between the combustion chamber and the heat exchanger.
 5. A boiler according to claim 4, wherein the pump is thermostatically controlled, the control thermostat being connected to the heat exchanger.
 6. A boiler according to claim 2, wherein the circulating pipe serves as a pump housing over a clearly defined area.
 7. A boiler according to claim 1 wherein a continuous flow heater is provided and having a mixing regulator between the pump and the suction aperture of the circulating pipe.
 8. The boiler according to claim 1, including a plurality of heat exchangers located within said housing, all below said combustion chamber. 